feat(simulation): contraband detection + dialogue confidence gate (D-075) (#425, #524)

Contraband detection (Task #425, D-065):
- New module: simulation/contraband.rs — NPC scan checks carried items
  against the KnowledgeGraph confidence gate. NPCs with Authority access
  can initiate a scan; scan outcome depends on item CarriedBy + KG entry.
- Adds ContrabandScanResult event type and ContrabanEntry component.
- Wired into simulation/mod.rs module list.

Dialogue confidence gate (Task #524, D-075 — OQ-18 resolution):
- relationship_to_trust() gains confidence parameter (KnowledgeConfidence).
- Trust tier mapping: (Friendly, KnowsDetails+)→Secret, (Friendly|Known,
  KnowsOf+)→Real, otherwise Surface. Access tier (Layer 1) unchanged.
- Caller process_talk_interaction passes observer KG confidence_of target.
- Resolves OQ-18: confidence co-gates TrustTier, not AccessTier.

Supporting changes:
- decisions/content.md: add D-075 (16 decisions, dated 2026-02-19)
- knowledge/types.rs: expose KnowledgeConfidence comparison helpers
- knowledge/registry.rs: minor API polish
- bridge/types.rs: ContrabandScanResult wire type
- bridge/text_renderer.rs: render contraband scan status
- perception/observer: include carried item count in snapshot
- npc/mod.rs: NPC scan range constant, authority flag

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

server/src/perception/observer/mod.rs

@@ -15,6 +15,7 @@ use crate::knowledge::{EntityRegistry, KnowledgeGraph, StableId};
 use crate::perception::cognitive_delay::CognitiveDelay;
 use crate::perception::query::{ActivePerceptionMode, VisibilityGeometry};
 use crate::perception::vision_cone::Facing;
+use crate::simulation::contraband::ScanEventBuffer;
 use crate::simulation::dialogue::DialogueResponseBuffer;
 use crate::simulation::interaction::NearbyInteractionBuffer;
 use crate::simulation::inventory::{CarriedBy, InventorySlot, ItemName};
@@ -68,6 +69,7 @@ pub fn compute_observer_snapshot(
             Option<&mut SprintAnomalyQueue>,
             Option<&CognitiveDelay>,
             Option<&mut DialogueResponseBuffer>,
+            Option<&mut ScanEventBuffer>,
         ),
         With<PlayerCharacter>,
     >,
@@ -92,6 +94,7 @@ pub fn compute_observer_snapshot(
         mut anomaly_queue_opt,
         cognitive_delay_opt,
         mut dialogue_response_opt,
+        mut scan_event_buffer_opt,
     )) = observer_query.single_mut()
     else {
         tracing::error!("compute_observer_snapshot: PlayerCharacter query failed");
@@ -168,6 +171,10 @@ pub fn compute_observer_snapshot(
 
     let current_monologue = monologue_buffer.take();
     let dialogue_response = dialogue_response_opt.as_mut().and_then(|buf| buf.take());
+    let scan_events = scan_event_buffer_opt
+        .as_mut()
+        .map(|buf| buf.take())
+        .unwrap_or_default();
 
     // Build pending recognitions from CognitiveDelay (#423, D-060)
     let pending_recognitions = cognitive_delay_opt
@@ -207,6 +214,7 @@ pub fn compute_observer_snapshot(
         pending_recognitions,
         dialogue_response,
         blocked_entities,
+        scan_events,
     });
 }
 

server/src/perception/observer/tests.rs

@@ -2106,10 +2106,7 @@ fn npc_behind_wall_appears_in_blocked_entities() {
         "NPC behind wall should appear in blocked_entities"
     );
     // Not in visible entities
-    let npc_visible = snapshot
-        .entities
-        .iter()
-        .any(|e| e.entity_id == npc_sid.0);
+    let npc_visible = snapshot.entities.iter().any(|e| e.entity_id == npc_sid.0);
     assert!(!npc_visible, "NPC should not be in visible entities");
 }